Hamas has claimed that three Israeli hostages - including a 10-month-old baby - have been killed in an airstrike on Gaza before a truce was announced six days ago.
The group's Al-Qassam Brigades said in a statement on Wednesday that baby Kfir Bibas, his four-year-old brother and their mother were killed in previous Israeli bombardment of the Gaza strip. Their father, who has also been held, was not mentioned in the statement.
Baby Kfir Bibas and his brother Ariel were snatched by the Hamas from their home during their October 7 attack on Israel.
The Israeli army said it is checking the claim by Al Qassam Brigades.
"The IDF (Israel Defense Forces) is assessing the accuracy of the information," the military said in a statement which said that it held Hamas responsible for the safety of all the hostages in Gaza.
Relatives had issued a special appeal for the family's freedom after the children and their parents were excluded from the penultimate group freed on Tuesday.
It comes after Hamas said they are willing to extend a truce for four more days, which would give them time to locate and free more Israeli hostages held by other terror groups, according to sources close to the negotiations.
If Israel agrees to this, Hamas "would be able to release Israeli prisoners that it, other resistance movements and other parties hold during this period, according to the terms of the truce," the source added.
Qatar's foreign ministry spokesman Majed Al Ansari told a Doha news conference on Tuesday that negotiators were seeking "a sustainable truce that will lead to further negotiations and eventually to an end... to this war."
An Israeli official said it would be impossible to extend the ceasefire, due to lapse on Thursday morning, without a commitment to release all women and children among the hostages.
The official said Israel believed militants were still holding enough women and children to prolong the truce by two to three days.
Egyptian security sources also said negotiators believed a two-day extension was possible.
Families of those Israeli hostages due to be released later on Wednesday had already been informed earlier of their names, the final group to be freed under the truce unless negotiators succeeded in extending it. Officials did not say at the time whether that included the Bibas family.
So far Gaza militants have freed 60 Israeli women and children from among the 240 hostages they seized under the deal that secured the war's first truce.
Twenty-one foreigners, mainly Thai farm workers, were also freed under separate parallel deals. In return, Israel has released 180 Palestinian security detainees, all women and teenagers.
Some of the hostages have been freed after 54 days in captivity. Last night, a new group of 12 Israeli and foreign hostages was freed from Gaza, with 30 Palestinians released by Israel.
The Israelis in the group were named as 36-year-old Rimon Kirsht, whose husband remains a hostage, Gabriela Leimberg, 59, and her daughter Mia, 17, who was filmed clutching her pet dog Bella.
The group also includes Mia's aunt Clara Merman, 63, Argentina-born Ofelia Roitman, 77, Ditza Herman, 84, Tamar Metzger, 78, Merav Tal, 53, Philippines-born Noralin Babdilla, 60, and Ada Sagi, 75, whose British son Noam has been campaigning in Israel and London for her release.
